Coating compositions used to form durable, i.e., abrasion and chemically resistant coatings are often deposited from sol-gel, i.e., solution-gelation, compositions. Such coatings are often deposited on plastic substrates, including transparent plastic substrates, which are often desired for a variety of applications, such as windshields, lenses, consumer electronic devices, among other things. To minimize scratching, as well as other forms of degradation, clear “hard coats,” as these coatings are often called, are often applied as protective layers to the substrate.
“Colored” or “tinted” hard coats are desired in some applications for aesthetic and other reasons. Such hard coats can be produced by imbibition of a colorant into a coated substrate by immersion of the substrate in a hot solution of the colorant or by depositing the colorant on the surface of the substrate and thermally transferring the colorant into the substrate. Depending upon the substrate material, however, such a process can result in an inconsistent color appearance and may impact the mechanical and/or chemical properties of the substrate. In addition, such a process can be complicated and can involve additional equipment, time and material.
It would be advantageous to provide tinted, abrasion resistant coating compositions suitable for produced a transparent tinted hard coat on a substrate. Moreover, it would also be desirable to provide such coating compositions that adhere directly to a plastic substrate, without the need of a primer layer, and which are stable, i.e., they do not solidify upon standing for a reasonable period of time.